Rock wool and composition for producing the same



Patented May 9, 1933 outrun 'srrss PATENT OFFICE.

EDWARD It, POWELL, OF ALEXANDRIA, INDIANA, ASSIGNOR T BANNER ROCK COR- PORATION, OF ALEXANDRIA,

INDIANA, A CORPORATION OF DELAWARE ROCK WOOL AND COMPOSITION FOR PRODUCING THE SAME No Drawing. Original application filed January 1927, Serial No, 159,228. Divided filed January 16, 1828. Serial No. 247,177.

This invention relates to a. method'of, and composition for producing a more stable and permanent rock or mineral Wool.

This application is a divisionof my patent application, Serial No. 159,228, filed J anuary 5, 1927,.and issued as U. S. Patent No. 1,656,828 on. Jan. 17, 1928.

Among the several objects of the invention may be noted the provision of a method and comosition for making a rock or mineral woo which is substantially free of sulphides and contains a high ratio of silica to basic materials, whereby the stability and permanencyof the compounds composing" the wool is increased. Other objects will be in part obvious and in part pointed out herelnafter',

Rockwool or mineral wool is made as described in said patent. The selected rock or sla is heated in a cupola furnace rovided Witi a charging inlet at let at the bottom through which the lluid roduct escapes. As the fluid product issues Tom the outlet, it is blown into the form of ZE long fibres which are cooled and collected as mineral wool, I

The theory and operation of the cupola is as, follows:

Argillaceous limestone containing (broadly) silica alumina, lime and magnesia (and a trace oii sulphur as an inherent impurity), or slag (containing higher percentages of sulphur as inherent impuritles) is loaded into the cupola in lump size.

It is to be understood that so-called rock wool is made directly from the rock which contains only a slight trace of sulphur; while so-called mineral wool is made from the sl a which contains hi her percentages of sulp ur. In either case, however, the sulphur may become detrimental to the resultmg wool product if the sul hur is permitted to take a sul hide form, alt ough a sulphate form is less armful. The term rock wool as used in the claims includes the product made from either rock or slag.

For instance, calcium sulphide is detrimental to the resulting wool composition be cause it tends to react with the dilute acids often found in the moisture of the atmosthe top all an out-.

'terial, which will melt and run down to and this application phere. This reaction gives off hydrogen sulphide gas which is soluble in the atmospheric moisture. Hence, if any large percentage of sulphides of calcium or other elements are contained in the Wool, it is rendered a substantially unstable composition or comi Y pound. Such a composition is therefore not a permanent or desirable material for purposes of construction. The sulphides also corrode many metals when wet, which is highly undesirable.

On the other hand, sulphates of calcium or other elements are harmless in the wool because they do not render it an unstable composition. There is little or no tendency for the action above described, to take place, that is, due to the presence of calcium sulphate or other sulphates. X

Inasmuch as sulphur is a widely diffused element present in most fuelsand many rocks at least in traces), it is desirable that the process of making rock or mineral wool be carried out so that none of the sulphur Will be reduced to the sulphide form; or if already present as a suphide, that it be oxidized to the sulphate form.

To carry the above principle into effect, the fuel is burned in a region such that complete combustion products of combustion contact with the raw material to be fused, that is, the fuel is burned in a separate combustion chamber, preferably with an excess of air; instead of being burned with the material (as has been done heretofore) by packing it into the cupola with said material. Hence substantially no reducing action takes place near the rock in the present invention. Incidentally, the sulphur content of the fuel is prevented from being added to that of the rock and product thereof, difficulties.

When sulphides are present in the raw rock or slag, it is necessary to oxidize them to sulphates if a sulphide-free rock wool is to be obtained. This cannot always be accomplished by an oxidizing flame, because heat may be received indirectly by the mgto aggravate the recited outlet without being oxidized.

takes place before the To prevent the abovedisadvantage, a fusible oxidizing agent is introduced with the rock, slag or other raw material at the charging door. Suitable oxidizin agents may comprise preferably solid so ium nitrate, sodium chlorate or manganese dioxide. These materials fuse with the melting rock and giveoii ox gen in the liquid, t ereby oxidizing the su phides present to sulphates.

As in the case of the excess air it isdesirable to use an excess of the a ove oxidizing agents so that the action is positively complete. All excess oxygen will bubble to the surface of the melt and pass off as a harmless gas.-

The liquid rock trickles from the rock charge in the cupola and forms a 001 from which the eiiiux at the outlet is fe As the charge in thecupola melts down, more raw rock may be fed in at the char ing door. The fresh rock is preheated by t e upflowing gases as said rock descends to the melting zone. v

In the above manner a sulphide-free liquid rock is made to flow from the outlet. The rock is blown into wool, collected, and treated to' remove small dro s or shot, suit abl asdescribed in my said patent.

nother point of novelty exists in the present invention, based upon the chemical proportions of the charge introduced into the fusion chamber or cupola 1. Up to this point, the nature of the rock charge has outlined.

prior art a typical wool would been only broadly For instance, 1n the analysis of resulting rock (more specifically) i 7 by w htand Subetanoe 3 Silicon oxide (sioo 4o acid) Aluminum oxide (M101) 11 neutral) Iron oxide (FeO) or (FeeOa)... 6

Calcium oxide (Ca 2i Magnesium oxide (M30); l8 Miscellaneous t Total 1m in its' a plications.

The above list shows a ratio of one part by weight to one ofsilicon oxide to basic materials. The result is that a tendency to slacking is had which disinteg'rates-the wool Another is that .the

wool wil decompose in dilute mineral acids.

The wool material resulting in the resent invention comprises a typical ana y'sis as follows:

I) lit and Subetanee Silicon oxide (Biol) s1 acid) Aluminum oxide (1mm 12 neutral) Iron oxide (FeO) 5 Calcium oxide (0a0).... 15 oi Magnesium oxide (MgO) 9 Misoellaneoul 2 TON 1N calcium and magnesium.

weig t of basic materials.

It will be seen that the above comprises practically a two to one ratio, actually 1.96 parts of silica to 1 art of basic materials which gives the resu ting'wool a more hard and glassy composition which will notslack or dissolve. A ratio of silica to basic materials of from one and one-half parts by weight to one, to two to one is suitable for preventing ,this slacking or disintegrating efiect. The improved composition is attained by selecting the pro er raw material, such as by adding a high si ica rock.

On a molecular ratio basis, the composition containing 57% by weight of silica contains approximately 1.60. molecular proportions ofsilica for each molecular proportion of materials of basic roperties as strong as those of the oxides of ferrous iron, calcium, and magnesium. This amount of silica is in excess of one and one-halfi molecular proportions for each. one molecular proportion of the basic oxides.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained;

As many changes could be made without departing from it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. A rock wool made from rock or a rock mixture containing 1 part b 7 weight of basic materials, calculated as oxi es of the metals, for approximately 2 parts of silica.

2. A rock wool made from rock or a rock mixture containing approximately 1.5 to 1.96 parts of silica to 1 part of oxides of iron,

3. A rock woo comprising silica and basic in the ratio of one and one-half to materials by weight of silica to one part by two arts rock 4. An oxidized wool comprising silica arid basic materials in the ratio of one and i arts by weight of silicate v one-half to two one part by weig t of basic materials.

In testimony whereof, I have si ned my name to this specificationthis 14t day of January, 1928.

EDWARD R. POWELL.

the scope of the invention, 

